ima: skip memory allocation for empty files
ima: skip memory allocation for empty files

Memory allocation is unnecessary for empty files.
This patch calculates the hash without memory allocation.

Signed-off-by: Dmitry Kasatkin <c116bc32ce0fd3cd5ab78828b5c5c631dc6f63d8@samsung.com>
Signed-off-by: Mimi Zohar <f02992f7c171053741caa6b515d9896745b37477@linux.vnet.ibm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs